1. Field of the Invention
The invention relates to a sensor having a housing in which a transmitting antenna array for transmitting electromagnetic transmission signals in a radiation area, and a receiving antenna array for receiving reception signals which are reflected at at least one object within the radiation area are arranged.
2. Description of the Related Art
Such sensors are increasingly used, in particular as radar sensors, for sensing the surroundings of vehicles. In the extreme short range, radar sensors are used to form parking aids. Furthermore, it is known that radar sensors can also be used to monitor the lane behind a vehicle and also next to a vehicle, in order, for example, to warn the driver of an automobile against risks of collision when overtaking, opening doors etc.
The sensors must generate transmission signals in a suitable way. It is known to transmit transmission signals in the form of an individual pulse and to determine the time after which a reflected reception signal has been received. The distance between the object and the sensor is determined from the time difference between the transmission and the reception of the pulse.
It is also known (DE 100 50 278 A1) to change the frequency of the transmission signals in a skilful way in order to be able to determine a location and a speed from the frequency of the transmission signal at the time when a reflected reception signal is received, and from the frequency of the reception signal. The transmission of the signals whose frequency has been changed can be carried out virtually continuously.
In order to monitor the various surrounding areas of a vehicle, it is thus necessary to use in each case different sensors which are provided with the corresponding controllers for shaping the transmission signals. This entails considerable financial outlay.